Hey Snowdog_2112,
This pretty much rules out a configuration issue. It is to do with the hardware that is incorrectly reporting fan state to the ESX layer. On the board documentation, is there a requirement that says all fan slots are to be populated? If not, is there a jumper setting or something that needs to be changed? If not, the next logical course of action would be to check with the hardware vendor to see if this is normal behaviour if all fan slots are not being used.
Regards
a